Drill bit



0f.6,1953 W.G.GREEN DRILL. BIT

5 Sheets-Sheet l Filed Sept. 26, 1947 i f xl' W. G. GREEN DRILL BIT oct; 6, 1953 3 sheets-sheet 2 Filed Sept. 26, 1947 grwwwbo@ Q7/m lmw v Patented Get. 6, 1953 UHTED STTS DRILL BIT Application September 26, 1947, Serial No. 776,314

2 Claims. (Cl. Z55-304) This invention relates to drill bits and more particularly to deep well bits of the type which include a plurality of rotatable cone cutters mounted on the bit head.

In the art of deep well drilling it is customary to rotate in the bore hole a hollow drill bit having a head portion provided with forks in each of which is mounted a spindle for supporting, for free rotation, a cutter cone having serrated faces for cutting or abrading the ground or rock in which the well is being drilled. Mud is supplied centrally to the drill bit and is discharged over the cutters to wash away the cuttings and to lubricate the exterior of the cutters. In view of the great weight which is transmitted to the cutters through their respective spindles, a bearing problem of considerable magnitude is presented. In attempts to solve this problem resort has been had to various bearing arrangements. While some of the bearing arrangements involve anti-friction elements which render the cutters` more freely rotatable, the resistance of these tov heavy shock has not been heretofore entirely satisfactory, with the result that frequent and costly replacements of the cutter cone assemblies have been necessary.

Another problem related to the bearing structure is that of lubricating the bearing surfaces between the cutter and spindle. These are customarily lubricated during assembly and are not susceptible of subsequent lubrication without disassembly. Thus it may be that some of the bearing failures heretofore frequently encountered were due to failure of lubrication.

It is an object of the present invention to provide a drill bit having a cutter and spindle assembly which is characterized by ease of assembly and installation, great mechanical strength, adequate turning freedom on the part of the cutter, very high resistance to shock and high resistance to bearing failure. This construction will also provide for disassembly to permit replacement of the cutter cone and spindle where desired.

It is contemplated, according to the present invention, to provide an improved cutter assembly which is susceptible of easy lubrication without disassembly and which may be lubricated during use.

Other objects and advantages of the invention will be apparent upon consideration of the following detailed description of several embodiments thereof in conjunction with the annexed drawings wherein:

Figure l is a View in vertical section of a deep 2 well drill bit constructed in accordance with the principles of the present invention, two of the cutter cones being removed for convenience of illustration;

Figure 2 is a bottom plan view of the drill bit of Figure 1;

Figure 3 is a view in section taken along the line 3 3 of Figure 1;

Figure 4 is a View in section similar to Figure 3 but illustrating a modied type of connection between the cutter cone and its supporting assembly;

Figures 5, 6 and 7 illustrate modifications of a compressible ring which is used in associating the cutter cone and is supporting assembly;

Figure 8 is a fragmentary view in vertical section of a drill bit and modified type of cutter cone assembly;

Figure 9 is a view in vertical section illustrating a step in the assembly of the apparatus of Figure 8; and

Figure 10 is a view in section taken along the line i-I 0 of Figure 8.

Now referring in greater detail to Figures l, 2 and 3 of the drawings, the reference numeral I0 designates a bit head having a tapered threaded shank portion I I adapted for attachment to the mud pipe of the drill rig and three forks I2, I3 and I4. The forks are provided respectively with tines I 2a and b, i3d and b and Mc and b, defining between them a space for the reception of a wedge-shaped spindle head such as the spindle head l5 of the cutter cone assembly shown in Figures 1 and 3. The bit head is hollow and is provided with a mud channel it; a manifold il and three mud discharge conduits I8, I9 and 2G for serving the several cutter cones to be mounted on the drill head.

The cutter cone assembly illustrated in Figures 1 and 3 is comprised of a cutter cone 2i provided with cutting teeth 22 and 23 arranged in rows about the outer surface. The exterior surface of the cutter cone and the teeth thereof are conventional, but the interior or base socket of the cone 2| is modiiled in accordance with the principles of the present invention so thatY the installation and operation of the cone affords certain advantages not heretofore known. Upon reference to Figures 1 and 3 it will be noted that the interior of the cutter cone 2l is generally cylindrical, terminating in a frusto conical end. The cutter cone is supported from a bearing assembly comprising a portion of the spindle head I5 and a spindle 24. The parts I5 and 2d are threaded together and hold between them a bearing ring 25. The spindle 24 includes a frusto conical head 24a, a threaded section 24h and a reduced diameter shank 24e. Spindle head member I includes a threaded section I5a.

The structure and operation of the cutter cone assembly of Figures 1 and 3 can best be understood by reference to the mode of assembly of the apparatus whichco'rnprises first the step of inserting the frusto-conical head 24a of spindle 24 in the frusto conical end socket of the cutter cone ZI. After the spindle has been placed in position a ring 25, which may be split at 25 as shown in Figure 5, is compressed to a reduced diameter and inserted in anannularV groove at 21 within the cutter cone ZI. 'Il'iereafterl the spindle head I5 is moved axially toward the spindle 24 until the threads of. I5a. and 24h engage, and thereafter the spindle 24 is rotatedY to pull the spindle head I5 toward it. Tothis end shank 24e of spindle 24 is provided with a screw driver kerf or yslot which indicated in Figure 3 by the reference character 28. This Operation may be performedl either before' or after the spindle head is inserted lcetv/eenthevv tines I2r1. and I2b 'of the'fork |21; After the-insertion of the wedge member between the-tines. of the fork i2, a weld` at 29 is made in order to fasten the spindle head to the fork;

It will be noted that the spindle'24 is-provi'ded Witha central channel. or conduitat and that the. conduit is provided atone end Witt-1.a tting 3| through which a lubricant may. be pumped to the bearing space between the-spindle and the cutter head'. Toassist inthe distribue tion of the lubricant between thespindle and 3;-,

the cutter, the spindleiisxprovidedwith'. helically cut grooves at 32. Similarly, grooves 33 are cut. in the portion of the spindle headf'which operates as a bearing forV the cutter cone 2 I. Packing is provided at 3A' and at' 35: to prevent the rapid escape of the lubricant fromthe bearing' surface during the operation of theJdrlill. lSirnilarly the ring 25 performsA somewhat the-sameY function.

It is now apparentV thatbecause the. ringi 25:

is seated in the groove 21 and is likewise clamped between the spindle head and the" spindle; the. cutter cone 2! is locked". against:axialifdisplaceement. It is further 'apparent that. a veryiiarge bearing surface is provided between. thefcut't'erf 'v cone and the spindle and spindle' head soA that.v satisfactory operationk during long; periods? of: use is achieved.

While in the foregoing. description refererrceif has been .made tobut. a single.- cutting` conegut` is apparent that each o-f the forks I'2gv I3. and. I4 will be provided with` a similar cone,- inthe construction of the bit.. ln'steaidcfs-a` splittiring such as is shown in Figure 5, it: is: apparent that a plurality of circumferenti'ally spacedarcuate. sections may be used to define a 'ringsuch-a's35;A shownV in Figure 6 or thatthesp'litiring maybe: provided. on itsL outer surface with". 'a groove; crt channel Ile which serves as' an. oil retention. groove and functions `further to. prevent the' toe' rapid migration of the' oil fromV th'een'd of; the? channel 3e to the' pack-ingv rin'gs ati 341iand 35T.. seeFigure 7. The arcuate section type-.of ring-,i is of particular utility in the case 'of'sjmall bits.l

Now referring to Figure 4,` there isf shown-1al modied form of the Ainvention 'involv-ingac'ut-- ter cone 4I, a spindle 42, a spindle head-'43 and! ball bearings 44. The cutter rIiI` correspande generally in configuration to the cutter .21| exsc'ept that instead of having "al groovesuch the groove 2'I therein, it has an arcuate groove defining a portion of a ball race. Complementary portions of the ball race are formed in the spindle 42 and in the spindle head 43, and the resulting ball race accommodates the balls 44 about which the cutter cone 4I can ro tate, and which prevent axial displacement of the cutt'erhead during operation. The attachnient of the spindle head to tlie tines of the fork of the bit is the same as that described in` connection with Figures 1-3 and therefore need not be further discussed or described in connection with Figure 4. As in the case of Figureixannular packing rings are provided to p'revent 'the 'escape of lubricant, and these are designated by the reference characters e6 and 41. The spindle 42. is provided with a central passageway at 48 having a grease fitting 49 and an` openend at 50 discharging into the bearing space between the cutter cone and the spindle. Thel assembly of the modified form of -apparatus shown iniFigure 4 corresponds to that described. in. connection with Figure 3 except that balls are inserted, rather than aring-7 prior` to the connection of*y the'spindle 42 to the spindle head 43. Helicalv grooves* for the distribution: of lubricantv correspond in structure and func` tionv to thosedescribed in connection with Fie* ure l3.

Now referring' to Figures, 9 and 10, there is shown a modification. of the construction inV which the lubricant isdi-ierently applied to` the: bearing; surface betweenv the;A cutter cones and thel spindle and in whichfthespindle and spindleheadv are` notl connected together by threading.. In Figure the portions of thefmainfbiti assem..l bly. which are shown, correspond. in` structureand. function to4 those described in.` connection withV .Figure l. .Accordingly-,.the-numeral '5Iv1is used to designate generallyr the bit'. assembly;

Within the bottom portion or the: drill. head- 5I.- th'ere provided a pressure accumulator V52: comprising a storage tank divided. intotwo* Working spaces-` byv a:- pist'on 53'` Thepist-on: is@ urged downwardly by as'prngi Eiland-is moved upwardly by liquid in the Working. space s' which. communicates: through. a: passageway 55 th'e'vdrilli-head and spindleheadrwith apas sageway 51: 'extending from. 'ai lubrication fit-- ting through. the? spindle head1 5'5: and. the' spindle. 6B?. Theworking spacer. iI having 'theresin: the spring.. 54l 'of' the pressure. accumulator 5'2,.islpruvided.with an. airs'ventat 522i.. It; cani: now be seen that. wh'en. lubricantzisprovided. under.` pressure' at.A fitting.: 5B,V nett only: will' it be pumped' througnthe passagewayto 'the bears-V ing.` between. the cutter cone. andi the.y spindle? and spindle; head, but `itiwillialso; be forced. up;-` wardl'ythrough the passageway? 55. tof. theA working. space 55, causing. the .pistonf tor-move. up:-V w'ardly against the thrust-l ofsprin'g 54 untillthe: space 55 iscompletely filled with: lubricant.' Thereafter: when thev drill- .is-n putinto use.. itisf apparent that as the lubricant works out from'. underneath. the cutter' cone, anyaddi'tionalisupply lis rendered available: by thestored: energy.'- in the springv 54 which will.pumplubricantrom the space 55. through. the passageways: and; 51 into the bearing space between the. cutter. cone and its'supporting. structure.

in additionl to 'the lubricationfeaturesiillus trated andfdescribed incmm'ectio .ithFi'gures 8-1'0 inclusive, .it is enoted.. that the r spindlemead: 59 is connected to the spindle l6fby."a.boss and.y sleeve arrangement'.V Aesleex/e: e3 on the.:l spindle head 59 extends between the spindle proper and a central, generally cylindrical boss member 64 attached thereto, or integral therewith. The boss 64 is provided with a series of spaced radial projections 65 disposed in an annular path about its outer surface. The surfaces of the members 65 are curved and a complementary curved groove is cut in the spindle 60. The circumferential spacing of the projection 65 allows for the distortion of the sleeve 63 which is indicated in Figure 10. It is now apparent that when the spindle 60 is to be attached to the spindle head 59, it is only necessary that the two be hammered together in the direction of the arrow indicated in Figure 9 to cause the sleeve 63 to be distorted in its passage around the spaced members 65 of the boss 66. This eiTects a relatively permanent locking of the core member to the Wedge member while the locking of the cutter cone against axial movement relative to the supporting assembly is effected as in Figure 3 by the use of a dual ring assembly designated in the drawings at 61. The oil distribution grooves and packings correspond generally to those shown in the preceding figures.

It will be noted that the sealing gaskets 34 and 35 shown in Figure 3, the gaskets 46 and 47 shown in Figure 4, and the gaskets or packings 68 and 69 shown in Figure 8 are so located that the thrust incident to the rotation of the cutter cone tends to compress them to improve their eiacy in prevening outleakage of the lubricant.

While the invention has been described with respect to but a few embodiments thereof, it is apparent that various modicaticns lie within the scope of the invention as dei-ined in the appended claims.

What is claimed is:

1. A drill bit comprising a head portion, a fork extending from said portion, a spindle head member secured to said fork at one end, a threaded section at the opposite end of said spindle head member, a spindle member including a frusto-conical head, a threaded section, and a shank forming a reduced portion of the outer end of the spindle member and adapted when assembled to extend substantially through an opening in the spindle head to the outer side of said head, a tightening tool slot in the end of said shank, said spindle head member threaded section engaging said spindle member threaded section by utilizing said tightening tool slot, a lubricating fitting positioned on the end of said shank, a longitudinal conduit in said spindle member leading from said lubrication fitting to the apex of said frusto-conical head, said spindle member defining a continuous bearing surface, said spindle head member defining a continuous bearing surface, said members dening therebetween a peripheral groove, a cutter cone mounted for relative rotation with said members, said cutter cone and spindle member being removable as a unit from said spindle head member, said cutter cone deiining inner bearing surfaces complementary to the bearing surfaces of said members, and a groove in registry with said peripheral groove, and a ring bearing means located between said members and lying in said grooves in close fitting relationship to absorb the axial thrust of said cutter cone and to act as a seal to restrict the passage of oil between the bearing surfaces of the spindle member and the spindle head member.

2. A drill bit as in claim 1 in which said ring includes a split so that its circumference can be reduced during assembly and the spindle can be inserted in the cutter cone and the ring then inserted and expanded into the groove of the cutter cone and iinally the spindle and spindle head connected together, said split being offset to present a continuous annular cross-section within its groove to restrict the passage of oil.

WILLIAM G. GREEN.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 930,759 Hughes Aug. 10, 1909 959,539 Hughes May 31, 1910 1,306,694 Hughes June 17, 1919 1,838,067 Wadsworth Dec. 22, 1931 1,896,231 Fletcher Feb. 7, 1933 1,909,128 Scott et al. May 16, 1933 2,000,076 Harrington May 7, 1935 2,058,624 Reed Oct. 27, 1936 2,061,933 Crum Nov. 24, 1936 2,065,741 Reed Dec. 29, 1936 2,065,742 'Reed Dec. 29, 1936 2,076,003 Reed Apr. 6, 1937 2,124,521 Williams et al July 19, 1938 2,132,498 Smith et al Oct. 11, 1938 2,174,102 Catland Sept. 26, 1 939 2,234,198 Reed Mar. 11, 1941 2,292,036 Behnke Aug. 4, 1942 OTHER REFERENCES Set of Pin-Bushings Showing Ample Lubrication Surface, drawing on page 26 of S-H Rotary Rock Drill Bit. 

